Device, system, and method for performing echo cancellation in different modes of a communication device

ABSTRACT

Methods and devices are disclosed for performing echo cancellation with a communication device for use by a hearing-impaired user. The communication device comprises communication elements, a memory device storing a plurality of sets of training parameters for an echo canceller, and a processor operably coupled with the communication elements and the memory device. The communication elements are configured to receive audio signals from a far end communication device, and to receive text captions corresponding to the audio signals from a relay service for display by the communication device during a call. Each set of training parameters corresponding to a different audio mode for the communication device. The processor is configured to execute an echo canceller by loading a first set of training parameters when a first audio mode is selected, and a second set of training parameters when a second audio mode is selected.

FIELD

Embodiments of the application relate to telecommunications and moreparticularly to communication devices configured to assisthearing-impaired users in communicating with others. More particularly,the application relates to improvements to echo cancellation in suchcommunication devices.

BACKGROUND

Hearing-impaired individuals may benefit from communication systems anddevices configured to provide assistance in order to communicate withother individuals over a communication network. For example, relayservices have been established to provide assistive services (e.g., textcaptions) to the hearing-impaired user communicating with acommunication device (e.g., caption phone, caption enabled device, etc.)that is specifically configured to communicate with the relay service.

In particular, a relay service may be a telecommunication intermediaryservice, which is intended to permit a deaf or a hearing-impaired personto utilize a normal telephone network. The relay service may include anoperator, referred to as a “call assistant,” who serves as a humanintermediary between the hearing-impaired user and a far-end user.During a captioning communication session, the call assistant may listento the audio signal of a far-end user and “revoice” the words of thefar-end user to a speech recognition computer program tuned to the voiceof the call assistant. Text captions (also referred to as “captions”)may be generated by the speech recognition computer as a transcriptionof the audio signal of the far-end user, and then transmitted to thecommunication device being used by the hearing-impaired user. Thecommunication device may then display the text captions while thehearing-impaired user carries on a normal conversation with the far-enduser. The text captions may allow the hearing-impaired user tosupplement the voice received from the far-end and confirm his or herunderstanding of the words spoken by the far-end user.

During a communication session, the microphone of the communicationdevice may experience echo (e.g., line echo, hybrid echo, acousticecho). If the audio signal captured by the microphone and transmitted tothe far-end user includes acoustic energy produced by the speaker, thefar-end user may hear an “echo” of his or her own utterances.Conventional acoustic echo cancellation (AEC) techniques are designed topredict and remove the echo from an electrical signal generated by themicrophone. In a communication device configured to assisthearing-impaired users, the issue of echo can present unique challengesdue to the much louder volume levels for the audio produced by thespeaker for the hearing-impaired user.

BRIEF SUMMARY

In some embodiments, the disclosure comprises a communication device.The communication device comprises communication elements, a memorydevice storing a plurality of sets of training parameters for an echocanceller, and a processor operably coupled with the communicationelements and the memory device. The communication elements areconfigured to receive audio signals from a far end communication deviceduring a call. Each set of training parameters corresponding to adifferent audio mode for the communication device. The processor isconfigured to execute an echo canceller by loading a first set oftraining parameters when a first audio mode is selected, and a secondset of training parameters when a second audio mode is selected.

Also disclosed is a method of performing echo cancellation of an audiosignal during a call. The method comprises determining a present audiomode from among a plurality of different audio modes for thecommunication device, loading a set of training parameters into an echocanceller corresponding to the present audio mode, performing echocancellation on a near-end audio signal of the communication devicewhile updating parameters of the echo canceller, and storing updatedparameters as a new set of training parameters for the present audiomode responsive to switching to a new audio mode.

Also disclosed is a communication system for facilitating communicationbetween a hearing-impaired user and a far-end user. The communicationsystem comprises a relay service configured to provide text captions ofa far-end audio signal associated with the far-end user, and a pluralityof communication devices associated with different hearing-impaireduser. Each communication device includes an electronic displayconfigured to display the text captions during a call, a speakerphone, ahandset, a memory device storing computer readable instructions andstoring a set of training parameters for each of a speakerphone mode anda handset mode of operating the communication device, and a processor.The processor is configured to execute the computer readableinstructions to control operations of the communication device,including executing an echo cancellation module configured to load theset of training parameters corresponding to the speakerphone mode whenthe communication device switches to the speakerphone mode, store a newset of training parameters in the memory device corresponding to thespeakerphone mode when the communication device switches away from thespeakerphone mode, load the set of training parameters corresponding tothe handset mode when the communication device switches to the handsetmode, and store a new set of training parameters in the memory devicecorresponding to the handset mode when the communication device switchesaway from the handset mode.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates a communication system configured to facilitate anassisted call between a hearing-impaired user and a far-end user.

FIG. 2 is a simplified schematic block diagram of a communication devicefor use by a hearing-impaired user according to an embodiment of thedisclosure.

FIG. 3 is a simplified block diagram of a communication device accordingto an embodiment of the disclosure.

FIG. 4 is a flowchart illustrating a method for performing echocancellation in an audio signal according to an embodiment of thedisclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which isillustrated specific embodiments in which the disclosure may bepracticed. These embodiments are described in sufficient detail toenable those of ordinary skill in the art to practice the disclosure. Itshould be understood, however, that the detailed description and thespecific examples, while indicating examples of embodiments of thedisclosure, are given by way of illustration only and not by way oflimitation. From this disclosure, various substitutions, modifications,additions, rearrangements, or combinations thereof within the scope ofthe disclosure may be made and will become apparent to those of ordinaryskill in the art.

In accordance with common practice, the various features illustrated inthe drawings may not be drawn to scale. The illustrations presentedherein are not meant to be actual views of any particular apparatus(e.g., device, system, etc.) or method, but are merely idealizedrepresentations that are employed to describe various embodiments of thedisclosure. Accordingly, the dimensions of the various features may bearbitrarily expanded or reduced for clarity. In addition, some of thedrawings may be simplified for clarity. Thus, the drawings may notdepict all of the components of a given apparatus (e.g., device) or alloperations of a particular method. In addition, like reference numeralsmay be used to denote like features throughout the specification andfigures.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof. Some drawingsmay illustrate signals as a single signal for clarity of presentationand description. It should be understood by a person of ordinary skillin the art that the signal may represent a bus of signals, wherein thebus may have a variety of bit widths and the disclosure may beimplemented on any number of data signals including a single datasignal.

The various illustrative logical blocks, modules, circuits, andalgorithm acts described in connection with embodiments disclosed hereinmay be implemented or performed with a general-purpose processor, aspecial-purpose processor, a Digital Signal Processor (DSP), anApplication Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein.

A processor herein may be any processor, controller, microcontroller, orstate machine suitable for carrying out processes of the disclosure. Aprocessor may also be implemented as a combination of computing devices,such as a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. When configured according toembodiments of the disclosure, a special-purpose computer improves thefunction of a computer because, absent the disclosure, the computerwould not be able to carry out the processes of the disclosure. Thedisclosure also provides meaningful limitations in one or moreparticular technical environments that go beyond an abstract idea. Forexample, embodiments of the disclosure provide improvements in thetechnical field of telecommunications. Embodiments include features thatimprove the functionality of the communication device such that newcommunication device and improved method for performing echocancellation are described, particularly in a telecommunication systemincluding a relay service for providing text captions to acaption-enabled communication device to assist hearing-impaired userswho may use different audio modes with different speakers that operateat relatively high volume levels for the hearing-impaired users. As aresult, the echo cancellation may be more tailored to individual audiomodes, particularly when switching audio modes at the beginning of acall or during a call.

In addition, it is noted that the embodiments may be described in termsof a process that is depicted as a flowchart, a flow diagram, astructure diagram, or a block diagram. Although a flowchart may describeoperational acts as a sequential process, many of these acts can beperformed in another sequence, in parallel, or substantiallyconcurrently. In addition, the order of the acts may be re-arranged. Aprocess may correspond to a method, a function, a procedure, asubroutine, a subprogram, interfacing with an operating system, etc.Furthermore, the methods disclosed herein may be implemented inhardware, software, or both. If implemented in software, the functionsmay be stored or transmitted as one or more instructions (e.g., softwarecode) on a computer-readable medium. Computer-readable media includesboth computer storage media and communication media including any mediumthat facilitates transfer of a computer program from one place toanother.

It should be understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not limit thequantity or order of those elements, unless such limitation isexplicitly stated. Rather, these designations may be used herein as aconvenient method of distinguishing between two or more elements orinstances of an element. Thus, a reference to first and second elementsdoes not mean that only two elements may be employed there or that thefirst element must precede the second element in some manner. Also,unless stated otherwise a set of elements may comprise one or moreelements.

As used herein, a “hearing-impaired user” may refer to a person withdiminished hearing capabilities. Hearing-impaired users ofcaption-enabled communication device often have some level of hearingability that has usually diminished over a period of time such that theycan communicate by speaking, but that they often struggle in hearingand/or understanding the far-end user.

The term “call” as used herein refers to the communication sessionbetween the hearing-impaired user's communication device and the far-enduser's communication device. The call may pass audio signals between thetwo parties. The term call is used in order to be more easilydistinguishable from the captioning communication session. At times, thecall may be referred to as incoming or outgoing from the perspective ofthe hearing-impaired user's communication device. Incoming and outgoingcalls may refer to the period of time prior to when the call is“answered” by the other party to begin the communication of the audiosignals therebetween.

The term “captioning communication session” as used herein refers to thecommunication session between the hearing-impaired user's communicationdevice and the relay service. The captioning communication session maypass text captions from the relay service to the hearing-impaired user'scommunication device. In some embodiments, the captioning communicationsession may also include the hearing-impaired user's communicationdevice transmitting the far-end user's audio signal to the relay serviceto generate the text captions.

The term “audio signal” (or voice signal) refers to the signal generatedand transmitted by a communication device during a call. Most examplesare provided from the perspective of a hearing-impaired user using acaptioning communication device, such that the audio signal captured bythat device is sometimes referred to as the “near-end audio signal,” andthe audio signal received to be reproduced by the speaker is sometimesreferred to as the “far-end audio signal.”

FIG. 1 illustrates a communication system 100 configured to facilitatean assisted call between a hearing-impaired user 102 and a far-end user104. The communication system 100 may include a first communicationdevice 110, a second communication device 120, and a relay service 130.The first communication device 110 and the second communication device120 may be coupled together to facilitate communication therebetween viaa first network 140. The first communication device 110 and the relayservice 130 may be coupled together to facilitate communicationtherebetween via a second network 150. For example only, the firstnetwork 140 and the second network 150 may each be implemented accordingto the standards and bandwidth requirements of a communication network(e.g., Public Switch Telephone Network (PSTN), cellular network, VoiceOver Internet Protocol (VOIP) networks, etc.). The use of the terms“network” or “communication network” as used herein contemplatesnetworks that are compatible and configured to provide communicationsusing analog and/or digital standards unless specifically statedotherwise. In some embodiments, the first network 140 and the secondnetwork 150 may be the same network (e.g., both connections may beInternet-based connections). Thus, discussion of the first network 140and the second network 150 separately may be for convenience ofdiscussing a particular connection between two or more devices. Ofcourse, in some embodiments, the first network 140 and the secondnetwork 150 may be different networks. For example, the firstcommunication device 110 and the second communication device 120 maycommunicate via a PSTN network connection, while the first communicationdevice 110 and the second communication device 120 may communicate viaan internet connection. Other variations and combinations of networksare also contemplated.

The first communication device 110 may include a device that isconfigured to assist the hearing-impaired user 102 in communicating withanother individual (e.g., far-end user 104). In some embodiments, thefirst communication device 110 may include a caption-enabledcommunication device configured to receive and display text captions ofat least a portion of the conversation. Thus, the hearing-impaired user102 may be able to read the text captions of the words spoken by thefar-end user 104 to supplement the far-end audio signal that isreproduced into sound by the first communication device 110. As aresult, the hearing-impaired user 102 may have an improved experience inunderstanding the conversation. Such an embodiment may be useful forpeople whose hearing has been damaged or decreased over time (e.g., theelderly); such that they can still speak but have diminished hearingthat makes it difficult to communicate. In some embodiments, the firstcommunication device 110 may also be configured to receive and displayvideo on an electronic display on the first communication device 110.

The second communication device 120 may comprise a conventional voicetelephone (e.g., landline phone, cellular phone, smart phone, VoIPphone, etc.). As such, the far-end user 104 may interact in aconventional manner with the second communication device 120. In someembodiments, the second communication device 120 may be configuredsimilarly as the first communication device (e.g., caption-enabledcommunication device). As a result, the second communication device 120may likewise be operated by a hearing-impaired user. Thus, althoughfacilitating communication between the hearing-impaired user 102 and thefar-end user 104 is shown in FIG. 1 to imply that the far-end user 104is a hearing-capable user, such a situation is shown only as an example.Other embodiments include both the first communication device 110 andthe second communication device 120 coupled to the relay service 130 tofacilitate the captioning services for each respective hearing-impaireduser (not shown). In such a situation, each communication device 110,120 may have its own communication session with the relay service 130.

The relay service 130 may be configured to provide interpretive services(e.g., captioning) to the hearing-impaired user 102. More specifically,a human “call assistant” within relay service 130 may be employed tofacilitate an assisted call between a hearing-impaired user 102 and afar-end user 104. As discussed above, in some embodiments the relayservice 130 may be configured to provide text captions of at least aportion of the conversation. In such an embodiment, the call assistantmay listen to the voice signal received and re-voice the portion of theconversation into a microphone so that voice recognition software maygenerate the text captions that are transmitted to the firstcommunication device 110. Thus, the relay service 130 may include one ormore of an interne protocol captioned telephone service (IPCTS),captioned telephone service (CTS), or other telecommunications relayservices (TRS).

FIG. 1 shows a configuration where the first communication device 110acts as a router for the voice signal from the second communicationdevice 120 to the relay service. In such an embodiment, the voice signalof the far-end user 104 may be transmitted from the second communicationdevice 120 to the first communication device 110. The voice signal ofthe far-end user 104 may then be transmitted from the firstcommunication device 110 to the relay service 130 for the text captionsto be generated in a text captioning embodiment. The text captions maythen be transmitted from the relay service 130 to the firstcommunication device 110 to be displayed as text captions for thehearing-impaired user to read during the conversation. The callassistant may also monitor the text captions that are generated andtransmitted to the first communication device 110 to identify any errorsthat may have been generated by the voice recognition software. The callassistant may correct such errors, such as described in U.S. Pat. No.8,379,801, issued Feb. 19, 2013, entitled “Methods and Systems Relatedto Text Caption Error Correction,” the disclosure of which isincorporated herein in its entirety by this reference. In someembodiments the relay service 130 may be configured to receive the voicesignal from the second communication device 120 and route the voicesignal to the first communication device 110. In some embodiments,another device may receive the voice signal from the secondcommunication device 120 and split the voice signal to route to both thefirst communication device 110 and the relay service 130.

In addition, although FIG. 1 shows only two communication devices 110,120, the communication system 100 may include more communicationdevices. It is contemplated that the communication system 100 mayfacilitate communication between any number and combinations ofhearing-impaired users and far-end users. For example, in someembodiments two or more communication devices may be connected forfacilitating communication between a hearing-impaired user and otherhearing-impaired users and/or far-end users.

Embodiments of the disclosure improve upon the typical communicationsystem by providing an improved method for echo cancellation within thefirst communication device 110. Depending on the mode (e.g., handsetmode, speakerphone mode, headset mode, etc.) in which the firstcommunication device 110 operates, different sets of training data maybe used in the echo cancellation module.

FIG. 2 is a simplified schematic block diagram of a communication device200 for use by a hearing-impaired user according to an embodiment of thedisclosure. For example, the communication device 200 may be the firstcommunication device 110 of FIG. 1. In particular, the communicationdevice 200 may be configured to establish calls with other communicationdevices and captioning communication sessions with a relay serviceconfigured to assist the hearing-impaired user. The communication device200 may be a caption enabled communication device, which may beimplemented as a standalone device (e.g., a caption phone), or asimplemented on another device (e.g., tablet computer, laptop computer,smart phone, etc.).

The communication device 200 may include a processor 210 operablycoupled with an electronic display 220, communication elements 230, amemory device 240, and input devices 250. In some embodiments, thecommunication device 200 may include a camera for also participating ina video communication session. The processor 210 may coordinate thecommunication between the various devices as well as executeinstructions stored in computer-readable media of the memory device 240.The processor 210 may be configured to execute a wide variety ofoperating systems and applications including the computing instructions.The memory device 240 may be used to hold computing instructions, data,and other information for performing a wide variety of tasks includingperforming embodiments disclosed herein. By way of example and notlimitation, the memory device 240 may include Synchronous Random AccessMemory (SRAM), Dynamic RAM (DRAM), Read-Only Memory (ROM), Flash memory,and the like. The memory device 240 may include volatile andnon-volatile memory storage for the communication device 200.

The communication elements 230 may be configured to communicate withother devices or communication networks, including other communicationdevices and the relay service. As non-limiting examples, thecommunication elements 230 may include elements for communicating onwired and wireless communication media, such as for example, serialports, parallel ports, Ethernet connections, universal serial bus (USB)connections IEEE 1394 (“firewire”) connections, Bluetooth wirelessconnections, 802.1 a/b/g/n type wireless connections, and other suitablecommunication interfaces and protocols. The input devices 250 mayinclude a numeric keypad, a keyboard, a touchscreen, a remote control, amouse, buttons, other input devices, or combinations thereof.

The communication device 200 may further include a plurality ofdifferent components through which the user may communicate. Inparticular, the communication device 200 may include a handset 260 and aspeakerphone 270. The handset 260 may be a handheld device having amicrophone for the hearing-impaired user to speak into and capture thenear end audio to transmit to the far-end communication device, as wellas a speaker for the hearing-impaired user to hear the far-end audioproduced by the speaker. The handset 260 may be coupled to the base unitof the communication device 200 through a cord or as a cordless handset.The speakerphone 270 may include a microphone and a speaker that areintegrated into the base unit of the communication device 200. In someembodiments, the communication device 200 may also be compatible tocommunicate with a headset 280 having its own speaker and microphone.The headset 280 is typically worn by the hearing-impaired user toposition the speaker close to the hearing-impaired user's ear and themicrophone close to the hearing-impaired user's mouth. The headset 280may be coupled to the base unit through a cord or as a cordless headset(e.g., via Bluetooth connection). In some embodiments, the headset 280may not include its own microphone. In such embodiments, the microphoneof the speakerphone 270 may be used.

The communication device 200 may be configured to be operated in one ofa handset mode, a speakerphone mode, and a headset mode according to thedesired method by the hearing-impaired user. Additional audio modes arecontemplated as other devices may be used to provide a speaker and/or amicrophone for the communication device 200. For example, a mobiledevice (e.g., smartphone, tablet, etc.) may be used to provide some ofthe functionality of the microphone and/or the speaker for thehearing-impaired user. In addition, different types of handsets orheadsets may be employed such that the processor may determine that aspecific handset or headset is in use and that a different set oftraining parameters may be saved for different types of handsets orheadsets. For example, a hearing-impaired user may have different typesof headsets that may be used by one or more different users of thecommunication device, such as a headset that may rest over the ear, beinserted into the ear, be connected to or integrated into eyewear or ahearing-aid, or another configuration. Each different type of headsetmay have different echo characteristics that may benefit frommaintaining a separate set of training parameters.

The hearing-impaired user may select the desired operating mode prior tothe call, and may even switch operating modes during the call. Each ofthe different modes creates a different acoustic environment for thecommunication device 200, which may cause different characteristics ofthe acoustic echo caused by the feedback (e.g., direct and/or indirect)from speaker to microphone. For example, the echo paths of the audiogenerated by the speakerphone 270 may be much different than the echopath of the audio generated by the handset 260. Likewise, if a headset280 is used, the echo path may also be different than the other modes.

Because the communication device 200 is configured primarily forhearing-impaired users, the effects and differences in the echocharacteristics may be even more different than the typical phonesystem. This is because the speakers used in the different components ofthe communication device 200 may include large gains in the amplifier,and produce louder volume levels than typical phones. For example, aspeakerphone having an amplified volume for hearing-impaired users maybe in a range of approximately 40 dB SPL to 50 dB SPL, or as much as 75dB SPL or more in some embodiments measured at 0.5 meter from thespeakerphone. A handset having an amplified volume for hearing-impairedusers may be in a range of approximately 80 dB SPL to 100 dB SPL, or asmuch as 115 dB SPL or more in some embodiments measured at an earreference point.

In order to reduce echo transmitted to the far-end device, an echocanceller is employed. In particular, the processor 210 is configured toexecute an acoustic echo canceller (AEC) that processes the near-endaudio signal generated by the microphone and filters out the portion ofthe near-end audio signal attributed to the echo from the environmentfrom the speaker. An AEC often employs one or more adaptive filters thatdynamically adjusts different parameters of the filter according to thechanging environment to achieve the desired filtering of the echosignal. In particular, the parameters of the adaptive filter areadjusted for the adaptive filter to converge to approach zero error inthe filter. An example of such an adaptive filter is described in U.S.patent Ser. No. 14/101,158, filed Dec. 9, 2013, and entitled “Methodsand Devices for Updating an Adaptive Filter for Echo Cancellation,” theentire disclosure of which is incorporated herein by this reference inits entirety. An additional example of an AEC include the different AECproducts offered by Adaptive Digital Technologies, Inc. of PlymouthMeeting, Pa. Examples of parameters that may used by the AEC may includefilter tap values, a filter step size, echo return loss estimate, echoreturn error estimate, filter coefficients used to adjust the adaptivefilter, echo characteristics (e.g., frequency, bulk delay, gain, etc.),various energy statistics used to gauge overall filter health, andcombinations thereof.

The processor 210 may be configured to determine which mode is inoperation, and load a different set of training parameters of the AECresponsive to each particular mode. As used herein, “trainingparameters” may be the parameters used to set the AEC at the beginningof a call or when a the communication device 200 switches to a differentmode during a call. For example, a first set of training parameters maybe loaded into the AEC for a handset mode, a second set of trainingparameters may be loaded into the AEC for a speakerphone mode, and athird set of training parameters may be loaded into the AEC for aheadset mode. The AEC may use the training parameters as a startingpoint for the call operating in the particular mode and adjust thedynamically adjust the parameters according. At the end of the operationof that particular mode (e.g., if the call is ended, if the userswitches modes during the call, etc.), the processor 210 may save theending state of the settings in the memory device 240 to be used as thetraining parameters for AEC the next time that the particular mode isused. As a result, the training parameters may be adjusted over time tobe in a state that is effectively the last known good state for aparticular mode. Each mode may have its own corresponding set oftraining data that is updated each time the mode is used. The result ofsuch switching and updating training parameters may be an improvement atthe beginning of a mode (e.g., beginning of a call or at the time ofswitching from another mode) as the starting point for the AEC may bemore tailored to the particular use case and environment. Theseimprovements may be even more apparent when generating the high volumelevels involved in communication devices for hearing-impaired users.Embodiments of the disclosure may also include similar switching ofmodes and loading of training parameters in other echo cancellationapplications, such as a hybrid echo canceller that uses an adaptivefilter that may have different training parameters for different modes.

FIG. 3 is a simplified block diagram of a communication device accordingto an embodiment of the disclosure. The handset 260 includes amicrophone 262 and a speaker 264. The speakerphone 270 includes amicrophone 272 and a speaker 274. The headset 280 may include amicrophone 282 and a speaker 284. Each of the handset 260, speakerphone270, and headset 280 may communicate with an echo cancellation module310 (executed by the processor 210 in FIG. 2). For example, the echocancellation module 310 may receive the far-end audio signal (passedonto each of the speakers 264, 274, 284) as well as each of the near-endaudio signals captured by each microphone 262, 272, 282. The source ofthe near-end audio signal used by the echo cancellation module 310 maydepend on which microphone 262, 272, 282 is currently in use for aparticular mode. In some embodiments, one microphone may be enabledwhile the others may be disabled. In some embodiments, each of thenear-end audio signal lines may be received by a multiplexer that passesthe appropriate near-end audio signal into the adaptive filter of theAEC according to the selected mode.

The memory device 240 may also be coupled to the echo cancellationmodule 310. The memory device 240 may have the different sets oftraining parameters stored therein corresponding to each of the modes.When a new mode begins, the corresponding set of training parameters maybe loaded from the memory device 240 into the echo cancellation module310, after which the parameters may be dynamically adjusted by the echocancellation module 310 such that the parameters may be transformed intodifferent values over time. At the end of the mode, the present valuesof the parameters may be stored in the memory device 240 as the lastknown good values of the parameters for that particular mode. As aresult, the present values of the parameters may replace the previousvalues of the training parameters. Thus, the next time that the mode isused, an updated set of training parameters may be loaded into the AECas its initial starting point.

FIG. 4 is a flowchart 400 illustrating a method for performing echocancellation in an audio signal according to an embodiment of thedisclosure. At operation 410, the processor may determine whether if anew call has been initiated, and further which audio mode is implementedat operation 420. For example, the current audio mode may be a handsetmode, a speaker mode, a headset mode, or other mode as desired. Atoperation 430, the current parameters of the AEC from the prior mode maybe reset. At operation 440, the set of training parameters for thecurrent mode may be loaded into the echo canceller as its starting pointfor the echo cancellation operation. The training parameters may be thelast known good position of the parameters corresponding to the prioruse of the communication device in the current mode. At operation 450,the processor may perform the echo cancellation on the near-end audiosignal prior to being sent to the far-end communication device. As aresult, the echo captured from the output of the speaker may be reducedas the echo cancellation operation adapts its parameters to convergetoward reducing the error of the echo canceller. The echo cancellationmay continue to be performed as long as the mode does not switch (e.g.,based on the call ending and/or the user actively switching the modeduring the call).

At operation 460, if the mode has been switched, the processor may storethe current settings of the echo canceller into a memory device. Thecurrent settings may replace the stored training parameters for theprior mode. For example, if the mode switches from handset mode tospeakerphone mode, the current settings of the echo canceller mayreplace the stored training parameters of the handset mode. If the modeswitch occurred due to the call being ended, at operation 480, theprocessor may end the call and await a new call. Otherwise, if the modeswitch occurred while the call is to continue, the processor may returnto determining the new mode and loading the set of training parametersfor the new mode before performing echo cancellation.

While certain illustrative embodiments have been described in connectionwith the figures, those of ordinary skill in the art will recognize andappreciate that embodiments encompassed by the disclosure are notlimited to those embodiments explicitly shown and described herein.Rather, many additions, deletions, and modifications to the embodimentsdescribed herein may be made without departing from the scope ofembodiments encompassed by the disclosure, such as those hereinafterclaimed, including legal equivalents. In addition, features from onedisclosed embodiment may be combined with features of another disclosedembodiment while still being encompassed within the scope of embodimentsencompassed by the disclosure as contemplated by the inventor.

What is claimed is:
 1. A communication device, comprising: communicationelements configured to receive audio signals from a far endcommunication device during a call; a memory device storing a pluralityof different sets of echo cancellation training parameters for anadaptive filter that performs echo subtraction for an echo canceller,each set of echo cancellation training parameters corresponding to adifferent audio mode for the communication device; and a processoroperably coupled with the communication elements and the memory device,the processor configured to execute the echo canceller by switchingbetween loading a first set of echo cancellation training parametersresponsive to a first audio mode being selected, and a second set ofecho cancellation training parameters responsive to a second audio modebeing selected, wherein the echo canceller is configured to: dynamicallyadjust the echo cancellation training parameters during echocancellation to have different values than the echo cancellationtraining parameters initially loaded into the echo canceller; and storethe different values as updated echo cancellation training parametersfor the corresponding set of echo cancellation training parameters ofthe selected audio mode responsive to exiting the selected audio mode.2. The communication device of claim 1, wherein the first audio mode isa handset mode corresponding to a handset being used, and the secondaudio mode is a speakerphone mode corresponding to a speakerphone beingused.
 3. The communication device of claim 2, wherein the processor isfurther configured to load a third set of echo cancellation trainingparameters when a third audio mode is selected.
 4. The communicationdevice of claim 3, wherein the third audio mode is a headset modecorresponding to a headset being used.
 5. The communication device ofclaim 1, wherein the echo canceller is an acoustic echo canceller (AEC).6. A method of performing echo cancellation of an audio signal during acall of a communication device, the method comprising: determining afirst audio mode for the communication device; loading a first set ofecho cancellation training parameters into an adaptive filter thatperforms echo subtraction for an echo canceller, the first set of echocancellation training parameters corresponding to the first audio mode;performing echo cancellation on a near-end audio signal of thecommunication device while updating parameters of the adaptive filter ofthe echo canceller from the first set of echo cancellation trainingparameters; exiting the first audio mode; storing the updated parametersfor the first set of echo cancellation training parameters for the firstaudio mode responsive to exiting the first audio mode; switching to asecond audio mode; loading a second set of echo cancellation trainingparameters into the adaptive filter, the second set of echo cancellationtraining parameters corresponding to the second audio mode; andperforming echo cancellation on the near-end audio signal of thecommunication device while updating parameters of the adaptive filter ofthe echo canceller from the second set of echo cancellation trainingparameters.
 7. The method of claim 6, wherein exiting the first audiomode is responsive to ending the call, and switching to the second audiomode occurs during a different call.
 8. The method of claim 6, whereinexiting the first audio mode and switching to the second audio mode isresponsive to a user selecting the second audio mode during the samecall.
 9. The method of claim 6, further comprising: exiting the secondaudio mode; storing the updated parameters for the second set of echocancellation training parameters for the second audio mode responsive toexiting the second audio mode; switching to a third audio mode; loadinga third set of echo cancellation training parameters into the adaptivefilter, the third set of echo cancellation training parameterscorresponding to the third audio mode; and performing echo cancellationon the near-end audio signal of the communication device while updatingparameters of the adaptive filter of the echo canceller from the thirdset of echo cancellation training parameters.
 10. The method of claim 6,further comprising resetting the adaptive filter of the echo cancellerprior to loading the second set of echo cancellation training parametersinto the adaptive filter of the echo canceller.
 11. The method of claim6, wherein the first audio mode and the second audio mode are differentaudio modes selected from the group consisting of a handset mode, aspeakerphone mode, and a headset mode.
 12. The method of claim 6,wherein the first set of echo cancellation training parameters are a setof last known good parameters from a prior use of the communicationdevice in the first audio mode.
 13. A communication system forfacilitating communication between a hearing-impaired user and a far-enduser, the communication system comprising: a communication serviceconfigured to provide text captions of a far-end audio signal associatedwith the far-end user; and a plurality of communication devicesassociated with different hearing-impaired users, each communicationdevice including: an electronic display configured to display the textcaptions during a call; a speakerphone; a handset; a memory devicestoring computer readable instructions and storing a different set ofecho cancellation training parameters for each of a speakerphone modeand a handset mode of operating the communication device; and aprocessor configured to execute the computer readable instructions tocontrol operations of the communication device, including executing anecho cancellation module configured to: load the set of echocancellation training parameters corresponding to the speakerphone modeinto an adaptive filter that performs echo subtraction for an echocanceller responsive to the communication device switching to thespeakerphone mode; load the set of echo cancellation training parameterscorresponding to the handset mode into the adaptive filter responsive tothe communication device switching to the handset mode; store an updatedset of echo cancellation training parameters in the memory device forthe first set of echo cancellation training parameters responsive to thecommunication device exiting the speakerphone mode; and store an updatedset of echo cancellation training parameters in the memory device forthe second set of echo cancellation training parameters responsive tothe communication device exiting the handset mode.
 14. The communicationsystem of claim 13, wherein the memory stores a third set of echocancellation training parameters for a headset mode, and wherein theecho cancellation module is configured to: load the third set of echocancellation training parameters corresponding to the headset moderesponsive to the communication switching to the headset mode; and storea set of echo cancellation training parameters in the memory device forthe third set of echo cancellation training parameters responsive to thecommunication device exiting the third mode.
 15. The communicationsystem of claim 13, wherein the speakerphone is integrally formed with abody of the communication device.
 16. The communication device of claim15, wherein the handset is coupled with the body of the communicationdevice through one of a cord or a cordless configuration.
 17. Thecommunication device of claim 1, wherein the different values stored foreach of the different audio modes correspond to a last known good statefor each of the different audio modes.
 18. The communication device ofclaim 1, wherein the echo canceller is configured to store the differentvalues as updated echo cancellation training parameters by replacing theecho cancellation training parameters prior to switching audio modes.19. The method of claim 1, wherein the processor is configured toexecute the echo canceller to between loading the first set of echocancellation training parameters and the second set of echo cancellationtraining parameters during the same call.
 20. The method of claim 8,further comprising: exiting the second audio mode; storing the updatedparameters for the second set of echo cancellation training parametersfor the second audio mode responsive to exiting the second audio mode;switching back to the first audio mode; loading the updated first set ofecho cancellation training parameters into the adaptive filter; andperforming echo cancellation on the near-end audio signal of thecommunication device while updating parameters of the adaptive filter ofthe echo canceller from the updated first set of echo cancellationtraining parameters.